Build, test, and debug regular expressions
Matches a three-line HTML/XML block: a line beginning with `<` (containing no other `<`), followed by the comment `<!-- Links -->`, then the start of the next line up to the first `>`. Typically used in editors or scripts to select, highlight, or extract the section marked by a 'Links' comment in templates and documentation. Requires PCRE2 due to the fixed-length lookbehind; the `g` flag finds all occurrences.